Hi all...I recently purchased a used 1996 Cal Spas hot tub. It was working great until about a week ago. Now I am having trouble with the secondary pump working properly. Whenever I hit the airswitch to turn it on, it just makes a loud humming noise and does not push any water through. I have found that if I loosen the one of the unions on the wet end and let a little water out, and try to turn it on again....it works normally. Whenever I break the union loose, I always notice a great deal of air escaping along with the water. I'm not sure if this has anything to do with the priming of the pump, but it just started about a week ago, and does it everytime I try to engage the pump. Thanks for any information you could give me...

-Jonathan

I've had a very similar situation as yours happen recently. I purchased a "new" pump (needless to say it was well used, just very clean), and when you ran it dry, it ran ok, but as soon as you put it under load, it would seize up and hum, as yours is doing. Basically 2 things can cause that to happen. Either you have a bad capacitor in the back cover of your pump, or, as in my case, the rear endbell of the motor that holds the motor bearing was shot, and when you loaded up the motor, it pulled the armature tight against the stator and that was it. If you feel daring, remove the capacitor, take it to a electric motor service shop, and they can test it, and if it's bad, they can supply you with a new one. If the capacitor is good, you can plan on getting a new motor, or you can take the motor apart, take the endbell to a machine shop, and most of the time they can sleeve it for ya for around 60 bucks. On a bad note, a lot of spas now days use sleeve bearings in the rear of the motors, and if this is your case, and it's bad, motor is shot.

I'm still wondering if that situation applies to me. My pump seems to run fine...it just requires that I open the unions on the wet end beforehand everytime I want to use it. Could it still be what you are describing....When I first press the button, the pump makes a humming noise with no water output. But as soon as I loosen the unions on it and let some water and air escape, it fires up like brand new.

It could be what yours is doing. When you open a union, you relieve the water resistance, thus reducing the startup torque required to get the motor to spin. Startup is the hardest for a motor. What you are doing is allowing it to come up to speed before applying full force to the pump, so the rotary inerta in the motor is enough to overcome the added resistance of the water.

Have you ever noticed the pump make kind of a rattle noise or a chattering noise while it comes up to speed? If so, I would really really suspect mechanical wear in the motor.

Have you had your capacitor(s) checked to be certain those are good? A bad capacitor can cause a startup hum and a no start condition under load. Under a no load, a bad capacitor may exhibit itself by an unusually long spin up time (time it takes to get to full speed). When a motor gets up to 70% of it's running speed, it disengages the capacitors, thanks to a centrifigal switch, and applies full power to the motor.

I would take the capacitor(s) in to be checked, since it's easy to get at, free, and perhaps the true cause of your problem.

charger_1....thanks for all the info. I really appreciate it. In response to your question, the motor does not exhibit any chattering or rattling noises when it engages. After I loosen the unions and let the water/air out and then retighten them, I hit the button and it comes on immediately with no problems at all. Hopefully that means that it is just a capacitor like you suspect. My next question would be, where is the capacitor, and how would I take it off?

Thanks again,
Jonathan

Depending on the brand of motor, the capacitors will be in one of 2 places. Most often they are under a cover that is on the rear of the motor, where the wires go through. They will look like a little cylinder, about an inch and a quarter in diameter, and about 2 to 3 inches long (typically) with two wires comming out of one end. If they aren't under the rear cover, then they may be on the side of the motor. The motor will look like it has a bump comming out of it, about half way back. This cover houses the capacitor and is held on by 2 or 4 screws, depending on the model.

It does NOT matter which way the wires are put back on, as there is no polarity. Some capacitors have 4 terminals forming 2 sets, with a rivit holding each set in the middle, so when you put the caps back on, make sure you you don't hook the two wires up to the same set.

I have some bad news...I can't get to the capacitor because of the motor's close proximity to the shell. I was going to just take the entire motor out, but I ran into another problem in doing so...I found that my T-valves are not holding at all, so I have no way of stopping the water flow when disconnecting the plumbing from the pump. Looks like I will have to wait until the next time I drain the tub for regular maintenance before I can take the motor out....

Sounds like you might just be losing your prime. Openign the union allows the air to escape, and bingo- it will puch water. Is the motor turning when you hear it "hum?" If so, it's getting air in there somehow... If not, keep following the capacitor route....

Update....I took the entire pump/motor to a local electrical shop, where they tested the capacitor. It was good. Yes, the motor makes a humming noise, but does not actually push water until I loosen the union a bit. Sorry for not posting lately as I recently almost died in a nasty car accident. I am almost totally recovered, but having a hot tub sure does help that process

OMG! Glad to hear you're still ticking...

Lets get that spa working, and speed along that recovery!


When I say you've lost your "prime", what that means is that air has somehow worked it's way into the wet end of your pump, and when the motor is energized, it spins just as it should, but since there is no water in the wet end, no vacuum is created, and no water moves....

So, what happens, the motor turns, it hums quietly, and no water moves.

Did you notice if the motor is turning or not when it hums? (regardless of water movement)
If it's turning, as I think it is, when you release the air, the pump "primes" and will work great!

But if it's humming and not spinning, the starting capacitor may be faulty.
When they tested it on the bench, it wasn't under load......
Sure sounds like it's just losing it's prime, make sure all unions are tight, and be sure you have enough water in the tub....

Good luck, with the spa, and most importantly, your recovery!